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Uncooled infrared detectors (IR) on a polyimide substrate have been demonstrated where amorphous silicon (a-Si) was used as the thermometer material. New concepts in uncooled microbolometers were implemented during the design and fabrication, such as the integration of a germanium long-pass optical filter with the device-level vacuum package and a double layer absorber structure. Polyimide was used...

In contrast to a global retreating trend, glaciers in the Karakoram showed stability and/or mass gaining during the past decades. This “Karakoram Anomaly” has been assumed to result from an out-of-phase temperature trend compared to hemispheric scales. However, the short instrumental observations from the Karakoram valley bottoms do not support a quantitative assessment of long-term temperature trends...

A systematic increase in global temperature since the industrial revolution has been attributed to anthropogenic forcing. This increase has been especially evident over the Himalayas and Central Asia and is touted as a major contributing factor for glacier mass balance declines across much of this region. However, glaciers of Pakistan’s Karakorum region have shown no such decline during this time...

In the current paper, we report the 1/f noise measurement of nichrome Ni/Cr (80/20 %) thin films for two types of pressure sensors: relative pressure sensors and absolute pressure sensors. The normalized Hooge coefficient for nichrome thin film was found to be 1.89 × 10−10 for the relative pressure sensors and 4.64 × 10−11 for the absolute pressure sensors. We demonstrated that the normalized Hooge...

In this paper, we have reported the design and simulation of uncooled microbolometer infrared radiation detectors. We have demonstrated several improvements in design over the conventional microbolometers such a double-layer absorption structure instead of single-layer absorber; a nanomesh radiation absorber to improve thermal isolation of the thermometer structure; device-level vacuum packaging which...

The fabrication and characterization of micromachined piezoresistive absolute pressure sensors in a flexible substrate is presented. A suspended aluminum oxide diaphragm containing nichrome (Ni-80%/Cr-20%) piezoresistive sensors backed by a vacuum cavity was utilized to form the sensor. The piezoresistors were placed in a half-Wheatstone bridge geometry to provide a linear response and thermal stability...

Pyroelectric infrared detectors provide the advantage of both a wide spectral response and dynamic range, which also has enabled systems to be developed with reduced size, weight and power consumption. This paper demonstrates the deposition of lead zirconium titanate (PZT) and lead calcium titanate (PCT) thin films for uncooled pyroelectric detectors with the utilization of gold electrodes. The modified...

This paper describes fabrication and characterization of self-packaged microbolometers on a flexible substrate. Amorphous silicon (a-Si) was used as the sensing material and the entire detector was device-level packaged in a vacuum cavity with an aluminum oxide packaging layer which can withstand up to 10 atm pressure. The flicker noise coefficient K1/f was calculated to be 1.23 ×10−13 for the a-Si...

Water wars are a prospect in coming years as nations struggle with the effects of climate change, growing water demand, and declining resources. The Indus River supplies water to the world’s largest contiguous irrigation system generating 90% of the food production in Pakistan as well as 13gigawatts of hydroelectricity. Because any gap between water supply and demand has major and far-reaching ramifications,...

Tree-rings are an important tool for the investigation of paleoclimatic records for regions or periods of time with no instrumental climatic data. However, the responses of different species and sites to various climatic parameters are unusual. In the present study, we developed tree-ring-width chronologies of Cedrus deodara from three different sites of Chitral Hindukush range of Pakistan. The study...

MEMS force sensors embedded in flexible polyimide substrates are reported, motivated by the need to monitor force and pressure on nonplanar surfaces for structural health monitoring. Details of the fabrication, measured preliminary results, and figures of merit are described. The sensors showed an average piezoresistive gauge factor of 1.75. The average value of normalized Hooge noise coefficient...

We investigated the composition of plant communities to quantify their relationships with environmental parameters in the Chitral Hindukush range of Pakistan. We sampled tree vegetation using the Point Centered Quarter (PCQ) method while understory vegetation was sampled in 1.5-m circular quadrats. Cedrus deodara is the national symbol of Pakistan and was dominant in the sampled communities. Because...

This paper reviews the most recent results on the fabrication and characterization of a variety of microelectromechanical (MEMS) based sensors fabricated on flexible polymer substrates without the loss of performance, towards the development of a smart skin. These sensors include amorphous silicon based temperature sensors; nichrome based piezoresistive, absolute pressure sensors, tactile sensors...

Steady and transient two-dimensional thin jet flow of a Newtonian fluid is examined numerically. The influence of inertia and gravity is emphasized. The fluid is assumed to emerge from a vertical channel, driven by a pressure gradient and/or gravity. The boundary layer equations are assumed for the thin film. In contrast to the commonly used depth-averaging solution method, the strong nonlinearities...

Polycrystalline ferroelectric modified lead titanate thin films have been deposited by pulsed laser deposition and annealed for pyroelectric infrared detection. The deposited thin films have been characterized for the temperature dependence of their pyroelectric parameters.

This paper presents the fabrication and measured performance of temperature sensors embedded in flexible polyimide substrates. The sensing material used for the temperature sensor was undoped amorphous silicon which was fabricated on a 35-m-thick layer of polyimide that serves as the flexible substrate. Another flexible polyimide superstrate layer of 35–40 m was spin-coated on top of the...

This paper describes the fabrication and characterization of micromachined, piezoresistive, absolute pressure sensors sandwiched between a flexible polyimide. The sensors are designed for structural health monitoring in aerospace applications. A suspended aluminum oxide diaphragm is utilized where nichrome (Ni-80%/Cr-20%) piezoresistive sensors are placed in a half Wheatstone bridge geometry to ensure...

The fabrication and characterization of micromachined, piezoresistive, relative pressure sensors sandwiched between flexible polyimide layers is described. This work is motivated by the need to monitor force and pressure on nonplanar surfaces for structural health monitoring. 35-nm-thick nichrome (Ni-80%/Cr-20%) is used as a sensing material for the pressure sensor. The average value of the gauge...

This paper presents the flicker noise or 1/f-noise measurement of RF sputtered amorphous silicon temperature sensors. The temperature sensor was fabricated between a polyimide substrate and superstrate to place it on a zero stress plane. The effects of flicker noise and voltage dependence of noise voltage power spectral density of the sensor were evaluated. The average value of flicker noise coefficient...

This study reports on the multivariate analysis of the vegetation of Hindukush Range in Pakistan, concentrating on the structure and regeneration potential of Monotheca buxifolia and associated tree species. Twenty stands at different locations in the Dir District of the Hindukush Range in Pakistan were chosen for the study. A point centered quarter method for trees and 5m × 5m size quadrats were...

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